The instant invention concerns an apparatus for manufacturing a blown synthetic hollow body with a closed bottom portion such as a liquid container, having a ring nozzle which opposite to a discharge device is arranged to be backwardly and forwardly movable, which, for the purpose of forming a head portion, is provided with a recess into which protrudes a backward and forward displacable inner member when it rests on a ring nozzle, as well as a multi-sectional blow mold, the blow mold sections thereof being laterally back and forth movable and being provided at the bottom portion at the height of the ring nozzle respectively with bottom portions.
In a prior art device of this type (German Patent No. 1,062,002), the bottom portions, when the blow mold sections are pushed together, do not contact each other but enclose a tubular gathering mold piece. The inner piece is a continuation of a blow needle which is guided into the discharge device and moves back and forth with the blow needle but is stationary relative to the recess of the discharge device.
The mandrel is also stationary and serves as sliding track for a stop portion which is backward and forward slidably arranged in order to change the width of the nozzle. In order to manufacture a bottom portion, the blow mold sections are spaced apart from each other by a small amount, namely, far enough so that it is possible to insert a loop or the like into the developing slot, which concentrically pulls together the gathering mold piece at the lower end, so that there develops then a tube with a closed bottom portion. However, this apparatus is not suitable if one intends to produce in the recess a gathering mold mouth piece, at the free end of which is proposed a front wall section which runs transverse to the longitudinal axis. Furthermore, the producing of the bottom portion is extremely costly.
It is also known in the prior art (Kautex Information 1, Special Print from "MASCHINEN MARKT" [Machinery Market] 75th Year, issue 8, 22 66/1969) to work a tubular gathering mold piece on a device without discharge section into the open and to move this form piece into a blow mold, the bottom pieces of which having extensions, which, when the blow mold sections are pushed together, contact each other to thereby form a bottom portion. Since the tube is here worked into the open area, it is often too long. This excess length is separated during the pushing together phase of the blow mold.
The excess length represents an excessively high usage of material.